John> Why am I getting tickets with a 1 day (86400 second) lifetime?
John> (I was trying to test with a short lifetime to see if some
John> ticket-renewing code was working correctly and waiting a day
John> to do each test is hopeless).

The krb5_get_in_tkt functions are deprecated; please use
krb5_get_init_creds functions instead. Also, what release are you
running? Some of the code in krb5_get_in_tkt_with_keytab() has
changed over time, possibly fixing bugs affecting your problem. I
believe that there was a bug in krb5-1.3 affecting
krb5_get_in_tkt_with_keytab() in exactly this way.

If you are seeing this behavior with a recent release, we would
appreciate hearing more details.

Some alternatives may include setting the KDC ticket lifetime for one
particular principal that you are testing.